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writeFileSync未创建和写入文件

next.js node.js

0

james emanon · 技术社区 · 4 年前

因此,我在Next.js中有一堆SSG页面,因此,我正在创建导航,其中有一堆路线。所以,我想“缓存”第一个api调用,然后只获取缓存的(写入文件数据)。我正在使用这个,它并没有创建文件。我得到了以下错误,因此,我总是点击api。

我登录捕获,它会给出错误。从不创建文件。

错误:

Error: ENOENT: no such file or directory, open '/Users/jim/company/clientapp/.next/server/pages/Users/jim/company/clientapp/.routes'

我的代码:

import fs from 'fs';
import path from 'path';

/* api */
import routes from '@api/rest/routes';

const ROUTE_CACHE_PATH = path.resolve('.routes');

export default async function getCacheRoutes() {
  let cachedData

  try {
    cachedData = JSON.parse(
      fs.readFileSync(path.join(__dirname, ROUTE_CACHE_PATH), 'utf8')
    )
      } catch (error) {
    // logger here
  }

  if (!cachedData) {    
    const data = await routes() // this is the api request, it works

    try {
      fs.writeFileSync(
        path.join(__dirname, ROUTE_CACHE_PATH),
        JSON.stringify(data),
        { flag: 'w' }. // With or without this, doesn't work.
      )
    } catch (error) {
      // Logger here
    }

    cachedData = data
  }

  return cachedData
}

0 回复 | 直到 4 年前

1

3

traynor 4 年前

它失败了,因为中的文件路径 ROUTE_CACHE_PATH 和 readFileSync 自始至终都是不正确的。

请尝试设置正确的路径,然后全程使用:

// setup the correct path to file, use it throughout
// writes to the file `routes` in CWD
const ROUTE_CACHE_PATH = path.resolve(path.join(process.cwd(), 'routes'));

现在请通篇参考:

fs.readFileSync(ROUTE_CACHE_PATH, 'utf8')

和

fs.writeFileSync(
ROUTE_CACHE_PATH,

请记住 JSON.parse 如果它不是您发送的可解析数据,那么这里也可能失败,所以您可能也会考虑添加一个处理程序,或者可能是在发送方。

有了这个代码,阅读和写作就有点独立了。因此,更好的方法可能是将文件写入错误部分IMHO:

try {
    readFile
} catch() {
    writeFile
}

这是重新排列的代码:

import fs from 'fs';
import path from 'path';

/* api */
import routes from '@api/rest/routes';

// setup the correct path to file, use it throughout
// writes to the file `routes` in CWD
const ROUTE_CACHE_PATH = path.resolve(path.join(process.cwd(), 'routes'));

export default async function getCacheRoutes() {

  // setup variables to be accessible for later
  let cachedData;
  let data;    

  // first, read the file
  // if it fails, there is no file
  // so move the file writing to the error part
  // note that parsing might also fail, so handle that there too
  try {
    // parsing might fail here though..
    cachedData = JSON.parse(
      fs.readFileSync(ROUTE_CACHE_PATH, 'utf8')
    )
  } catch (error) {

    // reading failed, handle file writing
    // parsing and other errors here
    console.log(error);

    // if there is no file, get data and write a fresh file
    if (error.code === 'ENOENT') {

      // todo: make sure it's always a JSON as string,
      // otherwise parsing will fail..
      data = await routes();

      try {
        fs.writeFileSync(
          ROUTE_CACHE_PATH,
          JSON.stringify(data), {
            flag: 'w'
          }
        )
      } catch (error) {
        // parsing might fail..
        console.log(error);
      }
    } else {
      // or some other error: JSON parsing failed, for example
      console.log('handle some other error', error);
    }

    cachedData = data;

  }

  return cachedData

}